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(No Model.) {Sheets-Sheet 1. P. E. DUGKHAM. DELIVERY APPARATUS FORPNEUMATIG GRAIN GONVEYERS.

No. 522,457. Patented July 3, 1894.

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UNITED STATES PATENT 'O-FFIcE.

FREDERIO ELIOT DUOKHAM, OF LONDON, ENGLAND.

DELIVERY APPARATUS FOR PNEUMATIC GRAIN-CONVEYERS.

SPECIFICATION forming part Of Letters Patent No. 522,457, dated uly 3,1894.

Application filed December 14, 1893. $erial No. 93,696-

To and whom it may concern.-

Be it known that I, FREDERIO ELIOT DUCK- HAM, civil engineer, ofMillwall Docks, London, England, have invented new and usefulImprovements in Pneumatic Apparatus for Elevating and Conveying Grainand other Matters, (for which I have obtained Letters Patent in thefollowing country, namely: British India, dated October 28, 1893, No.263,) of which the following is a full, clear, and exact description.

My invention relates to pneumatic apparatus for loading, unloading, andtransferring grain and other granular or pulverulent matters in bulk byan exhaust current of air, and consists of an improvement in theoscillating air-lock delivery box into which the said matters conveyedby the carrying current are deposited and by which they are delivered.Such an air-lock delivery box was described in the specification offormer Letters Patent of the United States of America, granted to me anddated the 8th day of March, 1892, No. 470,555, and was therein describedas an oscillating twinchambered receiver. It has been found that as eachchamber of the said oscillating air-lock delivery box is brought intoposition to receive a load, the contained air which replaced thepreviously discharged load and that which enters the chamber in the actof closing its discharge door, expands through the filling aperture intothe exhausted hopper from which the chamber is to be filled, and, byobstructing the passage of the grain or other matters about to enter thechamber of the air-lock delivery box, interferes with the continuousworking of the apparatus.

The object of the present improvement is to cause equilibrium of airpressure to be automatically established between the exhausted hopperand the chamber of the said air lock delivery box which is about to befilled therefrom, before said chamber arrives at the filling position.For this purpose, bypass passages in permanent connection with theexhausted hopper at a point above the lower conical part thereofcommunicate with ports in the seat of a valve on the oscillating airlockdelivery box, whereby communication is established between the chamberto be filled and the upper part of the hopper, while the (No model.)Patented in India October 28, 1893, No. 263.

air-lock delivery box is detained in an intermediate position by thecounterweighted latch mechanism by which the periodical oscillation ofthe delivery box is controlled. By this means the empty chamber isexhausted and its discharge door closed by external atmospheric pressurebefore said chamber arrives at the loading position and the equilibriumof pressure necessary to the uninterrupted working of the apparatus isestablished.

Reference is to be had to the accompanying drawings, forming part ofthis specification, Wherein Figure 1 is a part sectional elevation ofthe oscillating air-lock delivery box in its initial position, and Fig.2 is a similar view of the same apparatus in the second orintermediateposition.

The same letters of reference denote like parts in both figures.

A is the hopper wherein is deposited the grain or other matters enteringthrough the conveying pipe B, and to the top of which is connected theair exhausting pipe Bleading to the exhausting engine.

0 O are the chambers of the oscillating air lock delivery box to bealternately filled from hopper A. It rocks on a horizontal axis D and isprovided with a valve face E curved concentric to axis D and workingair-tight against a correspondingly curved seat F formed around theorifice a of the hopper A, the air lock delivery box being supported inposition during the filling, and its oscillation in opposite directionsbeing controlled, by appropriate detent mechanisms, each consisting of acounterweighted lover I, a catch 1, pendent therefrom, which engageswith a stud i and a slotted link 2" connected to the catch 2' and to afixed point for the purpose of withdrawing the catch t' from engagementwith the stud 2' when the load in the corresponding chamber overcomesthe counterweight.

So far, the apparatus is similar to that described in my former patentaforesaid.

The means by which eqilibrium of press ure is established between theempty chamber O or O and the hopper A before the aperture c or c of saidcompartment comes opposite the orifice a of the hopper A, comprisesby-pass chambers G G (or it may be a single ICO chamber) in constantcommunication by pipes II H withthe hopper at a point above the lowerconical part thereof A and with ports 9 9 opening through the valve seatF in such position that when the air lock delivery box is in its extremeposition, say, to the right, and the chamber 0' is being discharged, asshown in Fig. 1, the port g of the corresponding by-pass chamber isclosed by the portion of the valve face between the inlet apertures c cof the two chambers, while the aperture 0' of chamber 0' is uncovered toadmit air to said chamber. When, however, the chamber C is loaded tosuch an extent as to overcome the then emptied chamber 0' the air lockdelivery box rocks to the left until it is caught by the stud t at thatside resting on the latch 'i, as in Fig. 2. In this position theaperture 0' of the empty chamber 0 is closed to the external air and putinto communication with the bypass, port 9, whereby the chamber 0' isexhausted through G and pipe II to the upper part of hopper A therebycausing the discharge door of said chamber to close and establishingequilibrium of pressure between C and A, so that C is in readiness torcceive'a charge immediately on the air-lock delivery box falling overto its extreme position to the left, which is the converse of that shownin Fig. 1. The operation is similar in respect of the other chamber 0,the oscillation of the air-lock delivery box in each direction beingdivided into two stages and the delivery box remalnlng in the intermefording ample time for the establishment of the equilibrium of pressurebetween the other chamber and the hopper. I

In order that the air-lock delivery box may pass quickly from theextreme position to the intermediate position, it is free to move tothis extent uncontrolled by the counterweighted detent mechanism, whichis prevented by a stop 2' from coming into action until the intermediateposition is reached.

I claim- 1. In pneumatic apparatus for the conveyance of grain and otherpulverulent matters by an exhaust current of air, the combination, withthe oscillating two-chambered air-lock delivery box, and the exhaustedhopper from which its chambers are filled alternately with the mattersdeposited in the hopper by the conveying current, of a by-pass airpassage or passages in constant communication with l the upper part ofthe exhausted hopper, and a valve controlled by the oscillation of thedelivery box, whereby by-pass communication is established between thehopper and 1 the chambers of the air-lock delivery box alternately, soas to establish equilibrium of pressure between the empty chamber andthe hopper just before said chamber comes into position to be filled, asspecified.

2. The combination with the oscillating two-chambered air-lockdelivery'box, and the valve and apertures by which the alternatecommunication of its chambers with the exhausted supply hopper iscontrolled, of bypass ports in the valve seat in permanent communicationwith the exhausted hopper and situated in such position in the valveseat as to be both closed by the valve when the delivery box is ineither of its extreme positions, and put the one or other intocommunication with the inlet aperture of the chamber about to be filled,when the delivery box is in an intermediate position and the said inletaperture is closed to the external air, substantially as specified.

3. The combination, with the oscillating two-chambered air-lock deliverybox having a valve controlled by the oscillation of the receiver, andapertures by which its cliambers are put alternatelyinto communicationwith an exhausted supply hopper above, and by-pass airports in saidvalve seat communicating with the exhausted hopper and controlled by thesaid valve so as to establish bypass communication between the hopperand the one or other chamber of the delivery box,

at the moment when the delivery box is in" an intermediate position, ofcounterbalanced detent latch mechanism" whose operation is so limited asnot to oppose the free falling of the delivery box from the extremetothe intermediate position, as specified.

4. In a pneumatic grain-conveying apparatus, the combination of a hopperhaving a curved valve seat at its discharge end and provided with achamber on each side, said chambers being provided with ports in theirbottoms, pipes leading from the chambers to the hopper, and anoscillating and chambered delivery box having a curved and aperturedvalve face in contact with the seat of the hopper, substantially asdescribed.

5. In a pneumatic grain conveying apparatus, the combination of a hopperhaving a curved valve seat at its discharge end and provided with achamber on each side thereof, said chambers being provided with ports inj their bottoms, pipes leading from the chambers to the hopper, anoscillating and chambered delivery box having a curved valve faced topworking in contact with the seat of the hopper and provided withapertures leading to the compartments of the box, and a counterbalanceddetent latch mechanism for holding the delivery box in position,substantially as described.

Signed by the said Fnnnnmo ELIOT DUcK- HAM.

FREDERIO ELIOT DUCKHAM.

In presence of p G. F. WARREN, 17 Z Gracechurch Street, London, NotaryPub T. W. KENNARD, Clerk to A. M'. &' Wm. O'Zark, Patent Agents,

53 Chancery Lame, London.

